There are a number of advantages to replacing traditional (i.e., inorganic-based) electronic devices with those formed form organic materials (e.g., electroactive or conjugated polymers). For example, organic materials are generally lighter, more flexible, and cheaper to fabricate than inorganic materials. These materials and the devices produced therefrom, however, are not immune to the fabrication and/or integration challenges that exist for traditional electronics, especially with the ever-increasing demands of consumers for improved devices.
One such remaining challenge involves controlling the microstructure of organic materials in the solid state. Given the importance of microstructure on the intermolecular charge transport properties of films of conjugated polymers, the ability to control the microstructure of such materials should lead to improved conductivities or at least to similar conductivities with fewer charge carriers.
A common method for increasing the charge transport, or carrier mobility, in a polymer film entails thermally annealing the polymer at a high temperature, which is typically close to the glass transition temperature of the polymer, followed by a slow crystallization. This, however, requires the process to be conducted under extremely low oxygen and moisture concentrations so as to ensure that the polymer does not oxidize. Dielectric surface modifications using self-assembled monolayers provide another technique for mobility enhancement. Controlled deposition of monolayers, however, is often difficult to achieve and also requires moisture free environments. Other techniques include the use of high boiling point solvents, different deposition techniques, and the generation of ordered precursors in solution by using non-solvent aggregation. Unfortunately, the increases in mobility that are achieved by each of the above-referenced techniques are not significant. High mobility can be achieved by using high purity polymers with high regioregularity (e.g., greater than 98%), which can be process intensive to synthesize.
Thus, despite the advancements made in controlling the microstructure (and, by extension, the mobility) of organic materials in the solid state, there remains a need for improved methods for doing so. Such methods can lead to improved devices that exhibit higher mobilities and potentially higher conductivities. It is to the provision of such methods and devices that the various embodiments of the present inventions are directed.